325 research outputs found

    Physician Perceptions of ADHD Stimulant Diversion and Misuse

    Get PDF
    © The Author(s) 2016. Objective: The recent rise in ADHD has prompted concerns about adolescents with ADHD diverting and/or misusing stimulants. This is the first study to assess physician perceptions of the pervasiveness of these issues. Method: Questionnaires were mailed to a national sample of pediatric subspecialists. Responses were analyzed (n = 826; 18% response rate) using descriptive statistics and regression analyses. Results: In the past year, 59% of physicians suspected ≥1 patient(s) with ADHD diverted stimulants. Seventy-four percent believed ≥1 patient(s) feigned symptoms to obtain an initial ADHD diagnosis; 66% believed ≥1 patient(s) wanted stimulants to improve academic performance. Child and adolescent psychiatrists were most likely to suspect diversion and feigning symptoms. Thirty-nine percent of physicians believed diversion was at least “common.” Conclusion: Although many physicians suspected stimulant diversion and misuse, a substantial number were unaware of these issues, and subspecialist perceptions varied. These findings support the potential pervasiveness of these issues and the need for increased physician awareness

    Implicit incentives for fund managers with partial information

    Get PDF
    We study the optimal asset allocation problem for a fund manager whose compensation depends on the performance of her portfolio with respect to a benchmark. The objective of the manager is to maximise the expected utility of her final wealth. The manager observes the prices but not the values of the market price of risk that drives the expected returns. Estimates of the market price of risk get more precise as more observations are available. We formulate the problem as an optimization under partial information. The particular structure of the incentives makes the objective function not concave. Therefore, we solve the problem by combining the martingale method and a concavification procedure and we obtain the optimal wealth and the investment strategy. A numerical example shows the effect of learning on the optimal strategy

    Modeling vaccination rollouts, SARS-CoV-2 variants and the requirement for non-pharmaceutical interventions in Italy

    Get PDF
    Despite progress in clinical care for patients with coronavirus disease 2019 (COVID-19)1, population-wide interventions are still crucial to manage the pandemic, which has been aggravated by the emergence of new, highly transmissible variants. In this study, we combined the SIDARTHE model2, which predicts the spread of SARS-CoV-2 infections, with a new data-based model that projects new cases onto casualties and healthcare system costs. Based on the Italian case study, we outline several scenarios: mass vaccination campaigns with different paces, different transmission rates due to new variants and different enforced countermeasures, including the alternation of opening and closure phases. Our results demonstrate that non-pharmaceutical interventions (NPIs) have a higher effect on the epidemic evolution than vaccination alone, advocating for the need to keep NPIs in place during the first phase of the vaccination campaign. Our model predicts that, from April 2021 to January 2022, in a scenario with no vaccine rollout and weak NPIs (R = 1.27), as many as 298,000 deaths associated with COVID-19 could occur. However, fast vaccination rollouts could reduce mortality to as few as 51,000 deaths. Implementation of restrictive NPIs (R = 0.9) could reduce COVID-19 deaths to 30,000 without vaccinating the population and to 18,000 with a fast rollout of vaccines. We also show that, if intermittent open\u2013close strategies are adopted, implementing a closing phase first could reduce deaths (from 47,000 to 27,000 with slow vaccine rollout) and healthcare system costs, without substantive aggravation of socioeconomic losses

    The wiring diagram for plant G signaling

    Get PDF
    Like electronic circuits, the modular arrangement of cell-signaling networks decides how inputs produce outputs. Animal heterotrimeric guanine nucleotide binding proteins (G-proteins) operate as switches in the circuits that signal between extracellular agonists and intracellular effectors. There still is no biochemical evidence for a receptor or its agonist in the plant G-protein pathways. Plant G-proteins deviate in many important ways from the animal paradigm. This review covers important discoveries from the last two years that enlighten these differences and ends describing alternative wiring diagrams for the plant signaling circuits regulated by G-proteins. We propose that plant G-proteins are integrated in the signaling circuits as variable resistor rather than switches, controlling the flux of information in response to the cell’s metabolic state

    Initial investigation of athletes’ electrocardiograms acquired by wearable sensors during the pre-exercise phase

    Get PDF
    Aim: The aim of this study is to support large-scale prevention programs fighting sport-related sudden cardiac death by providing a set of electrocardiographic features representing a starting point in the development of normal reference values for the pre-exercise phase. Background: In people with underlying, often unknown, cardiovascular abnormalities, increased cardiovascular load during exercise can trigger sport-related sudden cardiac death. Prevention remains the only weapon to contrast sport-related sudden cardiac death. So far, no reference values have been proposed for electrocardiograms of athletes acquired with wearable sensors in the pre-exercise phase, consisting of the few minutes immediately before the beginning of the training session. Objective: To perform an initial investigation of athletes’ electrocardiograms acquired by wearable sensors during the pre-exercise phase. Methods: The analyzed electrocardiograms, acquired through BioHarness 3.0 by Zephyr, belong to 51 athletes (Sport Database and Cycling Database of the Cardiovascular Bioengineering Lab of the Università Politecnica delle Marche, Italy). Preliminary values consist of interquartile ranges of six electrocardiographic features which are heart rate, heart-rate variability, QRS duration, ST level, QT interval, and corrected QT interval. Results: For athletes 35 years old or younger, preliminary values were [72;91]bpm, [26;47]ms, [85;104]ms, [-0.08;0.08]mm, [326;364]ms and [378;422]ms, respectively. For athletes older than 35 years old, preliminary values were [71;94]bpm, [16;65]ms, [85;100]ms, [-0.11;0.07]mm, [330;368]ms and [394;414]ms, respectively. Conclusion: Availability of preliminary reference values could help identify those athletes who, due to electrocardiographic features out of normal ranges, are more likely to develop cardiac complications that may lead to sport-related sudden cardiac death

    Genome-Wide Quantitative Identification of DNA Differentially Methylated Sites in Arabidopsis Seedlings Growing at Different Water Potential

    Get PDF
    BackgroundIn eukaryotes, the combinatorial usage of cis-regulatory elements enables the assembly of composite genetic switches to integrate multifarious, convergent signals within a single promoter. Plants as sessile organisms, incapable of seeking for optimal conditions, rely on the use of this resource to adapt to changing environments. Emerging evidence suggests that the transcriptional responses of plants to stress are associated with epigenetic processes that govern chromatin accessibility. However, the extent at which specific chromatin modifications contribute to gene regulation has not been assessed.Methodology/Principal FindingsIn the present work, we combined methyl-sensitive-cut counting and RNA-seq to follow the transcriptional and epigenetic response of plants to simulated drought. Comprehensive genome wide evidence supports the notion that the methylome is widely reactive to water potential. The predominant changes in methylomes were loci in the promoters of genes encoding for proteins suited to cope with the environmental challenge.Conclusion/SignificanceThese selective changes in the methylome with corresponding changes in gene transcription suggest drought sets in motion an instructive mechanism guiding epigenetic machinery toward specific effectors genes

    Gα modulates salt-induced cellular senescence and cell division in rice and maize

    Get PDF
    Highlight textThis work reveals two distinct functions of Gα in NaCl stress in rice and maize: attenuation of leaf senescence caused by sodium toxicity in leaves, and cell cycle regulation by osmotic/ionic stress.The plant G-protein network, comprising Gα, Gβ, and Gγ core subunits, regulates development, senses sugar, and mediates biotic and abiotic stress responses. Here, we report G-protein signalling in the salt stress response using two crop models, rice and maize. Loss-of-function mutations in the corresponding genes encoding the Gα subunit attenuate growth inhibition and cellular senescence caused by sodium chloride (NaCl). Gα null mutations conferred reduced leaf senescence, chlorophyll degradation, and cytoplasm electrolyte leakage under NaCl stress. Sodium accumulated in both wild-type and Gα-mutant shoots to the same levels, suggesting that Gα signalling controls cell death in leaves rather than sodium exclusion in roots. Growth inhibition is probably initiated by osmotic change around root cells, because KCl and MgSO4 also suppressed seedling growth equally as well as NaCl. NaCl lowered rates of cell division and elongation in the wild-type leaf sheath to the level of the Gα-null mutants; however there was no NaCl-induced decrease in cell division in the Gα mutant, implying that the osmotic phase of salt stress suppresses cell proliferation through the inhibition of Gα-coupled signalling. These results reveal two distinct functions of Gα in NaCl stress in these grasses: attenuation of leaf senescence caused by sodium toxicity in leaves, and cell cycle regulation by osmotic/ionic stress

    The HPS electromagnetic calorimeter

    Get PDF
    The Heavy Photon Search experiment (HPS) is searching for a new gauge boson, the so-called “heavy photon.” Through its kinetic mixing with the Standard Model photon, this particle could decay into an electron-positron pair. It would then be detectable as a narrow peak in the invariant mass spectrum of such pairs, or, depending on its lifetime, by a decay downstream of the production target. The HPS experiment is installed in Hall-B of Jefferson Lab. This article presents the design and performance of one of the two detectors of the experiment, the electromagnetic calorimeter, during the runs performed in 2015–2016. The calorimeter's main purpose is to provide a fast trigger and reduce the copious background from electromagnetic processes through matching with a tracking detector. The detector is a homogeneous calorimeter, made of 442 lead-tungstate (PbWO4) scintillating crystals, each read out by an avalanche photodiode coupled to a custom trans-impedance amplifier

    Nucleon and Nuclear Structure Through Dilepton Production

    Get PDF
    Transverse momentum distributions and generalized parton distributions provide a comprehensive framework for the three-dimensional imaging of the nucleon and the nucleus experimentally using deeply virtual semi-exclusive and exclusive processes. The advent of combined high luminosity facilities and large acceptance detector capabilities enables experimental investigation of the partonic structure of hadrons with time-like virtual probes, in complement to the rich on-going space-like virtual probe program. The merits and benefits of the dilepton production channel for nuclear structure studies are discussed within the context of the International Workshop on Nucleon and Nuclear Structure through Dilepton Production taking place at the European Center for Theoretical Studies in Nuclear Physics and Related Areas (ECT*) of Trento. Particularly, the double deeply virtual Compton scattering, the time-like Compton scattering, the deeply virtual meson production, and the Drell-Yan processes are reviewed and a strategy for high impact experimental measurements is proposed

    Growth attenuation under saline stress is mediated by the heterotrimeric G protein complex

    Get PDF
    BackgroundPlant growth is plastic, able to rapidly adjust to fluctuation in environmental conditions such as drought and salinity. Due to long-term irrigation use in agricultural systems, soil salinity is increasing; consequently crop yield is adversely affected. It is known that salt tolerance is a quantitative trait supported by genes affecting ion homeostasis, ion transport, ion compartmentalization and ion selectivity. Less is known about pathways connecting NaCl and cell proliferation and cell death. Plant growth and cell proliferation is, in part, controlled by the concerted activity of the heterotrimeric G-protein complex with glucose. Prompted by the abundance of stress-related, functional annotations of genes encoding proteins that interact with core components of the Arabidopsis heterotrimeric G protein complex (AtRGS1, AtGPA1, AGB1, and AGG), we tested the hypothesis that G proteins modulate plant growth under salt stress.ResultsNa+ activates G signaling as quantitated by internalization of Arabidopsis Regulator of G Signaling protein 1 (AtRGS1). Despite being components of a singular signaling complex loss of the Gβ subunit (agb1-2 mutant) conferred accelerated senescence and aborted development in the presence of Na+, whereas loss of AtRGS1 (rgs1-2 mutant) conferred Na+ tolerance evident as less attenuated shoot growth and senescence. Site-directed changes in the Gα and Gβγ protein-protein interface were made to disrupt the interaction between the Gα and Gβγ subunits in order to elevate free activated Gα subunit and free Gβγ dimer at the plasma membrane. These mutations conferred sodium tolerance. Glucose in the growth media improved the survival under salt stress in Col but not in agb1-2 or rgs1-2 mutants.ConclusionsThese results demonstrate a direct role for G-protein signaling in the plant growth response to salt stress. The contrasting phenotypes of agb1-2 and rgs1-2 mutants suggest that G-proteins balance growth and death under salt stress. The phenotypes of the loss-of-function mutations prompted the model that during salt stress, G activation promotes growth and attenuates senescence probably by releasing ER stress
    corecore